Fuel Cell Plate Roughness and Porous Flow Fields for Low Resistance

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Solution Overview

Problem

Existing fuel cell technologies face challenges in reducing contact resistance between components, increasing the rate of chemical reactions, and preventing fuel/oxidant leakage, while also aiming to decrease manufacturing costs and stack thickness.

Innovation Solution

The use of uncoated 316 stainless steel alloy plates with specific surface roughness and porous structures in the electrochemical cell stack, including a cathode flow field with smooth regions facing the membrane electrode assembly and support features in the anode and cathode distribution channels, to enhance electrical contact and prevent leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plates are coated to lower contact resistance, then electrical contact resistance decreases, but manufacturing cost increases

Engineering Contradiction:

Improveelectrical contact resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the coating layer from the plate surface, extracting the problematic element that increases manufacturing cost while maintaining low contact resistance through the inherent plate surface properties and operating conditions

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The plate surface naturally maintains low contact resistance through its inherent properties and self-conditioning during operation, eliminating the need for external coatings or additional manufacturing steps

Inventive Principle:

Principle #25Self-service

2Reliability

If gasket thickness is increased to prevent puncture, then reliability against leakage improves, but overall stack thickness increases

Engineering Contradiction:

Improveleakage preventionVSAvoidstack thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The flow field structure is designed with preliminary protective features that prevent gasket puncture before it can occur, such as optimized channel geometry and support structures that distribute pressure and prevent concentration of stress at critical points

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent changes the structural parameters of the flow field and gasket interface, such as modifying channel depth, width, and curvature, to achieve adequate protection against puncture while maintaining thin gasket dimensions

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3740990B1Fuel-cell plate and flow structure designs

Publication Date: 2024.05.29 NUVERA FUEL CELLS LLC

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AI summary

The electrochemical cell stack has electrochemical cells stacked along a longitudinal axis. The electrochemical cells have a membrane electrode assembly (MEA) with a cathode catalyst layer, an anode catalyst layer, and a polymer membrane therebetween. The electrochemical cells have an anode plate and a cathode plate with the MEA interposed therebetween, and a cathode flow field between the cathode plate and catalyst layer. The anode plate or the cathode plates are formed of uncoated 316 stainless steel. Portions of the cathode or anode plate have an arithmetic average roughness from about 5 μin to about 35 μin. The cathode flow field is a porous structure. Surface regions on a side of the porous structure facing the MEA are smooth and align with a subgasket of the MEA.